Method of and apparatus for drying pulp articles



Aug 20, 1929 G. J. MANsoN 1,725,465

'METHD OF AND APPARATUS FOR DRYING PULP ARTICLES Filed Deo. 8, 1927 divi l l0 J" ed I f I H f/Z l /M/fA/rap.

650065. M4/usan /9 M www Patent-ed Aug. 20, UNITED STATES 1,125,465PATENT OFFICE.

GEORGE JAMES MANSON, OF HAWKESBURY, ONTARIO, CANADA.

METHOD OF AND APPARATUS FOR DRYING PULP ARTICLES.

.Application led December 8, 1927. Serial No. 238,659.

This invention relates to an improved method of and apparatus for dryingpulp articles, and the objects of the invention are toy rapidly andeconomically dry pulp articles without distorting the same, or spoilingthe surface thereof; and it consists essentiall of drying articlesthrough the heat pro uced by electrical currents induced in the portionof the die adjacent to the article, all as hereinafter more fully setforth and described in the accompanying specification and drawings.

At present articles made from pulp fibres are taken from the formingmachines and are dried by subjecting the article to hot air in a closedchamber, er by carrying the article on a moving belt through a chambercontaining hot air. These chambers may have steam coils in them, to heatthe drying air or air which'has been heated outside of the chamber maybe continuously circulated through the chamber. When a pulp article isdried by these methods, it is likely to come from the drier a littledistorted and with a rather rough surface.

Attempts to dry pulp articles in dies heated by resistance coilsdirectly connected to al source of electrical energy have been tried,but it has been impossible due to the small size of the dies, to getenough energy into them to be able to operate the dies continuously andmake theprocess commercial. 1y feasible.

I have found that if the dies containing the article to be dried areplaced in -a strong magnetic field which will induce a current in thepart of the die next to the pulp article, the pulp article will be driedvery rapidly on account of the high temperature to whichl the adjacentpart of the die is raised by the heavy induced current. v Practicallyany shaped article can be more rapidly and economically dried by thismethod than by hot air. The finish of the article is much better andthere is no distortion of the shape of the article.

In the drawings, Figure 1 is'an elevation of one form of apparatus inwhich the invention may be carried out. i

Fi re 2 is a sectional elevation through the evice with the pulp articletherein.

Figure 3` is a plan view of one of the dies. Referring Ato the drawings,A indicates a t of transformer which may be used to evelop the necessarymagnetic eld, having able that as heav inafter referred to.

It will be understood that the form of transformer is shown by wayofillustration only, and may be varied to suit the conditions, and thatany other well known type of transformer may be used. .Figure 2 shows asection through the drylng dies, of which l5v is the upper and C thelower die, preferably formed of wrought iron or mild steel, and faced onthe surface adjacent to the pulp article with metal of high conductivitysuch as sheet copper, the facing of sheet copper being indicated at 14and 15.

It is desirable to guard against the formation of eddy currents in thevdies' B and C, and this may conveniently be done by slotting the dies aslshown by radial slots 16 in the dies for this purpose. The copperlinings 14 and 15 are not slotted, as it is desira current as possibleshould flow throng 1 them.

faces 14 and 15 andl may be either formed therein by pressure betweenthe dies exerted in suitable hydraulic press or may be placed in thedies after being transversely formed in another press.

lVhen it is desired to dry the article, the dies B and C containing thesame, are placed between pole faces A1 and A2 of the trans former A, andthe coils 11 and 12 are excited .by alternating current passedtherethrough,

the magnetic force produced from this current flowing between the facesA1 and A2 through the dies B and C, and causing a heavy current to beinduced in the copper plates 14 and 15, causes these plates to rapidlyincrease in temperature, giving up heat` The pulp article 17 is locatedbetween the I 'As many changes could be made in the above construction,and many apparently widely different embodiments of my invention, withinthe scope of the claims, con-X, structed without departing from thespirit or scope thereof, it is intended that all matter contained in theaccompanying specification and drawings shall be interpreted asillustrative and not in a limiting sense.

What I claim as my invention is:

1. The herein described method of drying4 pulp articles, comprising-placing the same between a pair of dles and lnducing heavy secondaryIelectrical current 1n the dies and expelling the moisture therefrom.

2. The herein described method of drying pulp articles, lwhich compriseslacing the same between dies, heating surfaces of increased electricalconductivity and inducing heavy secondary electrical heating currents inthe surfaces.

3. The herein described method of drying pulp articles, which comprisesplacing the article between apair of dies, inducing heavy secondaryelectrical heating current in the gies, then exerting a pressure betweenthe ies.

4. An apparatus for the purpose specified, comprising a pair of dieshaving copper facesadjacent to the article to be dried, and means forinducing electricall currents in the said faces.

memes- 5. rhe'herein described method of drying a pulp article, whichcomprises placing the same between a pair of dies adapted to allow theevaporated water to escape therefrom, forming a complete magneticcircuit including a portion of the die surface, inducing a heavysecondary electrical current' in the said magnetic circuit to therebyheat the pulp' article and expel the moisture thererom. 6. An apparatusVfor the purpose specified, comprising a pairpof dies adapted to permitthe escape of vapour therefrom, a magnetic circuit associated with thedies including part of the die surface, means for inducing a heavysecondary electrical current in the said magnetic circuit to heat thepart in the die and expel the moisture therefrom out of the die.

7. In an apparatus of the character described, a pair of dies, havingmeans adapted to guard against the formation of eddy currents therein,and adapted to permit the escape of moisture therefrom, a magneticcircuit associated with the dies, and means for inducing a heavysecondary `current in the said magnetic circuit to heat,the article inthe dies and expel the moisture therefrom.

8. An apparatus for the purpose specified comprising a transformerhaving opposite pole faces between which dies are-adapted to lit, aprimary heating c oil surrounding the pole faces, a pair of dies adaptedto iit between the pole faces and to have electrical currents inducedtherein by the said primary windings, means for exerting a pressure'between the -pole faces, and the dies provided with copper workingsurfaces.

In witness whereof I have hereunto set my hand. l

. GEORGE JAMES MANsoN.

